The present invention relates to a plasma display device used in a broadcast receiver or for image display, to a luminescent device excited by a rare gas resonance UV beam or a low-speed electron beam, and to an image display system using the display device and the luminescent device.
In recent years, a plasma display device using a plasma display panel (hereinafter simply referred to as PDP) has been mass-produced as a flat-panel display device used in a broadcast receiver or a computer terminal or for image (video) display.
The plasma display device performs color display by causing a phosphor disposed in an extremely small discharge space containing a rare gas in the PDP to emit light by using, as an excitation source, a short-wavelength UV beam (which has a resonance line at 147 nm or 172 nm if xenon is used as the rare gas) generated in the negative glow region of the discharge space.
In the PDP of the plasma display device, the resonance line of a rare gas shorter in wavelength than the resonance line of mercury vapor, which is at 253.7 nm, or the like is used as an excitation source for the phosphor. The short wavelength limit thereof is the wavelength of the resonance line of helium, which is 58.4 nm.
An exemplary structure of the gas discharge cell is as shown in “Technology & Materials of Color Plasma Display Panel” published by CMC Publishing Co. Ltd. A representative structure thereof is shown in FIG. 9. FIG. 9 is an exploded perspective view showing the structure of a typical surface-discharge color plasma display device (PDP). The PDP shown in FIG. 9 is a reflective PDP obtained by bonding a front glass substrate 10 and a rear glass substrate 20, each composed of a glass substrate, to each other in integral relation and forming phosphor layers 24, 25, and 26 in red (R), green (G), and blue (B) colors, respectively, on the rear glass substrate 20.
A pair of sustaining discharge electrodes 11 and 12 are formed in parallel to have a specified distance therebetween on the surface of the front glass substrate 10 opposing the rear glass substrate 20. The pair of sustaining discharge electrodes 11 and 12 are composed of transparent electrodes. Opaque bus electrodes 13 and 14 for compensating for the conductivity of the transparent electrodes are provided in superimposing relation on the sustaining discharge electrodes 11 and 12.
These electrodes 11 to 14 are covered with a dielectric (such as lead glass) layer 15 for AC driving. The dielectric layer 15 is provided with a protection film 16 made of a magnesium oxide (MgO).
Magnesium oxide (MgO), which is high in resistivity for sputtering damage and in secondary electron yield, functions to protect the dielectric layer 15 and lower a discharge initiation voltage.
The rear glass substrate 20 has, on the surface thereof opposing the front glass substrate 10, a group of electrodes consisting of address electrodes 21 which are orthogonal to the pair of sustaining discharge electrodes 11 and 12 on the front glass substrate 10. The address electrodes 21 are covered with a dielectric layer 22. Barrier ribs 23 for separating the address electrodes 21 from each other are provided on the dielectric layer 22 to prevent the expansion of a discharge (define a region for the discharge). The barrier ribs 23 are composed of a low-melting glass and formed with equal spacings to have the same heights and identically configured sidewalls.
The phosphor layers 24, 25, and 26 are coated successively in stripes in such a manner as to cover the groove surfaces between the barrier ribs 23. The formation of the phosphor layers 24, 25, and 26 is performed by coating, on the rear glass substrate 20 having the address electrodes 21, the dielectric layers 22, and the barrier ribs 23 formed thereon, phosphor pastes prepared by mixing phosphor particles forming the phosphor layers 24, 25, and 26 and vehicles by a method such as screen printing and then removing a volatile component therefrom by baking.
A discharge gas (a gas mixture of, e.g., helium, neon, xenon, and the like) is sealed in the discharge space between the front glass substrate 10 and the rear glass substrate 20, though it is not depicted in FIG. 9.
In the PDP, a discharge cell (a unit light-emitting region or a discharge spot) is selected by either one of the sustaining discharge electrodes 11 and 12, e.g., the sustaining discharge electrode 12 and the address electrode 21 and a gas discharge is caused repeatedly in the selected discharge cell through a sustained discharge between the sustaining discharge electrodes 11 and 12.
A vacuum UV beam resulting from the gas discharge excites the phosphor layers in the region so that visible emission is obtained. Color display is obtained by combining emission of each of unit cells having the red, green, and blue phosphor layers 24, 25, and 26 corresponding to the three primary colors.
Color PDPs which have been improved increasingly in performance year after year are replacing direct-view cathode ray tube color televisions. For the PDPs to be widespread as major large-scale televisions for home use as television broadcast receivers, they should have a higher moving-picture quality and a longer lifetime.